Introduction: How to Polish Acrylic Pen Blanks for a Scratch Free Finish
After many years of testing out different polishing methods for Alumilite (and other acrylics), I've finally narrowed the process down to three main steps: Sanding, Polishing and Buffing. This process is both quick and easy, but the most important part is it is reliable. I hope you enjoy this little walk through of my method. There are may ways to polish up a pen, but this is the best I've found so far.
Step 1: Sanding
Once you have shaped the blank on the lathe, the first step to getting a flawless finish is to level everything out and get rid of any tool marks or ridges that may have been left during the shaping process. I typically start out at 240 grit, but this step depends on what the surface is like. Minor tool marks can be removed quickly with 240 grit, but if there are deeper ridges you can start at a lower grit. Once all the tool marks have been removed and the blank is flattened out, I move on to 400 grit. Make sure to blow off or wipe off the blank between grits to ensure that none of the lower grit particles remain on the blank.
I find Abranet sandpaper to be the best choice for sanding, but any sandpaper will do. Abranet seems to last longer than typical sandpaper, and it is less prone to clogging up. You can also clean out any clogged areas quickly by blowing it out with air.
Step 2: Polishing
Begin the polishing stage by using a wet/dry sandpaper or polishing paper. I prefer 3M polishing paper for this step, but Micro Mesh or silicone carbide sandpaper works fine as well. Starting out with the lowest grit of 3M polishing paper, which is approximately P700-P750 grit, apply water or a similar lubricant to the paper and begin polishing out the 400 grit scratches.
Once all the 400 grit scratches have been removed, it's time to move up to the second grit, approximately P1350 grit. Make sure to wipe off the slurry and water on the blank between grits to ensure that no lower grit particles remain on the blank.
Step 3: Buffing
The final step in the process is using buffing wheels to remove all the fine scratches left behind with the polishing paper. Begin with a buffing wheel charged with Tripoly buffing rouge. Carefully hold the blank in your fingers or create a mandrel to hold the blank and buff it along the length of the blank. This is perpendicular to the scratches left while polishing the blank on the lathe.
Once all the lower grit scratches have been removed with the Tripoly wheel, it's time for the final step. Put the final touches on the blank using another buffing wheel charged with white diamond buffing rouge. The white diamond leaves a flawless surface on the blank bringing the gloss out on it.
Step 4: Extra Tips
Overall, this process is both fast and effective. The sanding and polishing process prepares the surface for a flawless finish, and the buffing wheels bring out the high gloss shine in the blanks. After years of trial and error, this method has proven to be the fastest and most reliable way to get a scratch free polish on Alumilite blanks. This works exactly the same for top coat finishes such as CA glue or lacquer, as well as other acrylics and resins.
One quick tip for getting the best results is to keep the lathe speed down around 500-700 rpms. Sanding and polishing at high speeds can lead to heating the blank up and clogging of the sandpaper/polishing paper. When running the lathe slower, the sandpaper will abrade more evenly with less clogging.